OTTAWA — Toronto’s year and a half of political tumult, which began with a video that showed Mayor Rob Ford smoking crack cocaine, ended on Monday when voters rejected a bid by his brother to maintain the family’s hold on City Hall. John Tory, a center-right candidate, emerged as the winner by a margin of about 16 percent.Mr. Ford, after months of denials, admitted last November that he had smoked crack. But he not only rejected calls for his resignation, he also sought re-election as mayor until last month. Mr. Ford stepped aside after learning that he had a rare form of cancer. Doug Ford, his brother and a City Council member, replaced him on the mayoral ballot.There was one victory for the Ford family. Rob Ford, who is undergoing chemotherapy, secured the City Council seat now held by his brother.Mr. Ford is to remain mayor until the end of November, at least in title. Last year he was stripped of all but ceremonial powers by the City Council. Police evidence and news reports have shown that Mr. Ford, who often joked about his drinking, used drugs on more than one occasion, was prone to bouts of extreme intoxication and sometimes drove while drunk.